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mkfs.vfat: fix volume label to be padded with space

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The specification requires volume label to be space padded.

Latest fsck.vfat will remove the zero padded volume label
as invalid. See also:
https://github.com/dosfstools/dosfstools/issues/172

Make the default label also "NO NAME" which has the special meaning
that label is not set.

function                                             old     new   delta
mkfs_vfat_main                                      1470    1502     +32
static.NO_NAME_11                                      -      12     +12
.rodata                                           104309  104318      +9
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/0 up/down: 53/0)               Total: 53 bytes

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Timo Teräs 2022-01-21 13:17:00 +02:00 committed by Denys Vlasenko
parent 6dd6a6c42d
commit 78fdf4d22d
1 changed files with 17 additions and 8 deletions
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25
util-linux/mkfs_vfat.c
View File

@ -218,8 +218,11 @@ static const char boot_code[] ALIGN1 =
int mkfs_vfat_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
{
static const char NO_NAME_11[] = "NO NAME ";
struct stat st;
const char *volume_label = "";
const char *arg_volume_label = NO_NAME_11; //default
char volume_label11[12];
char *buf;
char *device_name;
uoff_t volume_size_bytes;
@ -257,14 +260,17 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
opts = getopt32(argv, "^"
"Ab:cCf:F:h:Ii:l:m:n:r:R:s:S:v"
"\0" "-1", //:b+:f+:F+:h+:r+:R+:s+:S+:vv:c--l:l--c
NULL, NULL, NULL, NULL, NULL,
NULL, NULL, &volume_label, NULL, NULL, NULL, NULL);
/*b*/NULL, /*f*/NULL, /*F*/NULL, /*h*/NULL, /*i*/NULL,
/*l*/NULL, /*m*/NULL, /*n*/&arg_volume_label,
/*r*/NULL, /*R*/NULL, /*s*/NULL, /*S*/NULL);
argv += optind;
// cache device name
device_name = argv[0];
// default volume ID = creation time
volume_id = time(NULL);
// truncate to exactly 11 chars, pad with spaces
sprintf(volume_label11, "%-11.11s", arg_volume_label);
dev = xopen(device_name, O_RDWR);
xfstat(dev, &st, device_name);
@ -459,7 +465,7 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
(int)media_byte,
volume_size_sect, (int)total_clust, (int)sect_per_clust,
sect_per_fat,
(int)volume_id, volume_label
(int)volume_id, volume_label11
);
}
@ -508,7 +514,7 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
STORE_LE(boot_blk->vi.ext_boot_sign, 0x29);
STORE_LE(boot_blk->vi.volume_id32, volume_id);
memcpy(boot_blk->vi.fs_type, "FAT32 ", sizeof(boot_blk->vi.fs_type));
strncpy(boot_blk->vi.volume_label, volume_label, sizeof(boot_blk->vi.volume_label));
memcpy(boot_blk->vi.volume_label, volume_label11, 11);
memcpy(boot_blk->boot_code, boot_code, sizeof(boot_code));
STORE_LE(boot_blk->boot_sign, BOOT_SIGN);
@ -545,15 +551,18 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
// root directory
// empty directory is just a set of zero bytes
memset(buf, 0, sect_per_clust * bytes_per_sect);
if (volume_label[0]) {
// create dir entry for volume_label
// not "NO NAME", "NO NAME " etc?
// (mkfs.fat 4.1 won't create dir entry even with explicit -n 'NO NAME',
// but will create one with e.g. -n '', -n ' zZz')
if (strcmp(volume_label11, NO_NAME_11) != 0) {
// create dir entry for volume label
struct msdos_dir_entry *de;
#if 0
struct tm tm_time;
uint16_t t, d;
#endif
de = (void*)buf;
strncpy(de->name, volume_label, sizeof(de->name));
memcpy(de->name, volume_label11, 11);
STORE_LE(de->attr, ATTR_VOLUME);
#if 0
localtime_r(&create_time, &tm_time);